Systems and apparatuses for mitigating LiDAR noise, vibration, and harshness

ABSTRACT

An isolation system for a light detection and ranging (LiDAR) optical core assembly is provided. The LiDAR optical core assembly comprises a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics. The isolation system comprises a polygon-motor base element coupled to the polygon-motor rotating element and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element. The plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 63/187,847, filed on May 12, 2021, entitled “SYSTEMS AND APPARATUSES FOR MITIGATING LIDAR NOISE, VIBRATION, AND HARSHNESS,” the content of which is hereby incorporated by reference in its entirety for all purposes.

FIELD OF THE TECHNOLOGY

This disclosure relates generally to optical scanning and, more particularly, to an isolation system for a light detection and ranging (LiDAR) optical core assembly.

BACKGROUND

Light detection and ranging (LiDAR) systems use light pulses to create an image or point cloud of a surrounding environment. Some typical LiDAR systems include a light source, a light transmitter, a light steering system, and a light detector. The light source generates a light beam that is directed by the light steering system in particular directions when being transmitted from the LiDAR system. When a transmitted light beam is scattered by an object, a portion of the scattered light returns to the LiDAR system as a return light pulse. The light detector detects the return light pulse. Using the difference between the time that the return light pulse is detected and the time that a corresponding light pulse in the light beam is transmitted, the LiDAR system can determine the distance to the object using the speed of light. The light steering system can direct light beams along different paths to allow the LiDAR system to scan the surrounding environment and produce images or point clouds. LiDAR systems can also use techniques other than time-of-flight and scanning to measure the surrounding environment.

SUMMARY

A vehicle-based LiDAR device may include an optical core assembly comprising a high-speed polygon-motor rotating element and a galvo. For various vehicle-based applications, the polygon may rotate at speeds between about 3000-12000 revolutions per minute during the operation of the optical core assembly. At the same time, the galvo may also oscillate or rotate at very high speeds to steer light reflected by the polygon in particular directions. Because of these operational conditions, the polygon and galvo may tend to generate undesirable acoustic noises and vibrations. Furthermore, the LiDAR device may also be subject to imbalances, noises, shock displacements, vibrations, or other harsh conditions during the operation of the vehicle. One or more of the noises, shocks, vibrations, lateral wobbles, or other harsh conditions may cause displacement of the elements and/or parts of the LiDAR optical core assembly and may thus further affect the smoothness and control of the operation of the LiDAR optical core assembly. This may in turn affect the accuracy and overall performance of the LiDAR device. Thus, there is a need to eliminate or reduce the impact caused by these conditions.

A LiDAR device comprising an isolation system and a LiDAR optical core assembly is provided. The isolation system may be implemented to improve the stability and reliability of the polygon-motor rotating element of the LiDAR optical core assembly, enhance the capability of the polygon-motor rotating element to operate under highly variable environmental conditions, and improve the overall performance of the LiDAR device.

In various embodiments, a LiDAR device may be positioned at various locations on an exterior surface of vehicle. For example, one exemplary location for optimal scanning performance and Field-of-View (FOV) may be on a top surface of a vehicle (e.g., an exterior surface of the roof of the vehicle). Such a top surface location may extend above the roof line of the vehicle but remain relatively close to the driver's (or another front passenger's) seating position within the vehicle. Therefore, the rooftop placement of the LiDAR device may be relatively close to a driver's/front passenger's head (and ears) such that unwanted and/or excessive acoustic noise and vibration from the LiDAR device can be transmitted through the car roof structures and be very disturbing to the driver or other vehicle passengers during vehicle operation.

Embodiments of the present disclosure use an isolation system configured to isolate the noises caused by the various environmental conditions (e.g., imbalances, noises, shock displacements, vibrations, or other harsh conditions), thereby reducing the likelihood of undesirable optical core assembly performance. In one embodiment, an isolation system for a light detection and ranging (LiDAR) optical core assembly is provided. The LiDAR optical core assembly comprises a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics. The isolation system comprises a polygon-motor base element coupled to the polygon-motor rotating element and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element. The plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.

In one embodiment, a light detection and ranging (LiDAR) scanning system is provided. The LiDAR system comprises an isolation system. The isolation system is used for a light detection and ranging (LiDAR) optical core assembly. The LiDAR optical core assembly has at least a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics. The isolation system comprises a polygon-motor base element coupled to the polygon-motor rotating element and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element. The plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.

In one embodiment, a vehicle comprising a light detection and ranging (LiDAR) scanning system is provided. The LiDAR scanning system includes an isolation system. The isolation system is used for a light detection and ranging (LiDAR) optical core assembly. The LiDAR optical core assembly has at least a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics. The isolation system comprises a polygon-motor base element coupled to the polygon-motor rotating element and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element. The plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.

Various embodiments of the present disclosure are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present application can be best understood by reference to the figures described below taken in conjunction with the accompanying drawing figures, in which like parts may be referred to by like numerals.

FIG. 1 illustrates one or more exemplary LiDAR systems disposed or included in a motor vehicle.

FIG. 2 is a block diagram illustrating interactions between an exemplary LiDAR system and multiple other systems including a vehicle perception and planning system.

FIG. 3 is a block diagram illustrating an exemplary LiDAR system.

FIG. 4 is a block diagram illustrating an exemplary fiber-based laser source.

FIGS. 5A-5C illustrate an exemplary LiDAR system using pulse signals to measure distances to objects disposed in a field-of-view (FOV).

FIG. 6 is a block diagram illustrating an exemplary apparatus used to implement systems, apparatus, and methods in various embodiments.

FIGS. 7A-7B illustrate various views of a motor vehicle with an exemplary LiDAR system having an isolation system disposed in a vehicle according to an embodiment of the present disclosure.

FIGS. 8A-8D illustrate various views of an exemplary isolation system for a LiDAR optical core assembly according to an embodiment of the present disclosure.

FIGS. 9A-9C illustrate various views of another exemplary isolation system for a LiDAR optical core assembly according to another embodiment of the present disclosure.

FIG. 10 illustrates an exemplary isolation system for a LiDAR optical core assembly with a base according to another embodiment of the present disclosure.

FIGS. 11A-11B illustrate various views of an exemplary isolation system for a LiDAR optical core assembly with a base and an enclosure according to another embodiment of the present disclosure.

DETAILED DESCRIPTION

To provide a more thorough understanding of the present invention, the following description sets forth numerous specific details, such as specific configurations, parameters, examples, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention but is intended to provide a better description of the exemplary embodiments.

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise:

The phrase “in one embodiment” as used herein does not necessarily refer to the same embodiment, though it may. Thus, as described below, various embodiments of the disclosure may be readily combined, without departing from the scope or spirit of the invention.

As used herein, the term “or” is an inclusive “or” operator and is equivalent to the term “and/or,” unless the context clearly dictates otherwise.

The term “based on” is not exclusive and allows for being based on additional factors not described unless the context clearly dictates otherwise.

As used herein, and unless the context dictates otherwise, the term “coupled to” is intended to include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements). Therefore, the terms “coupled to” and “coupled with” are used synonymously. Within the context of a networked environment where two or more components or devices are able to exchange data, the terms “coupled to” and “coupled with” are also used to mean “communicatively coupled with”, possibly via one or more intermediary devices.

Although the following description uses terms “first,” “second,” etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first sensor could be termed a second sensor and, similarly, a second sensor could be termed a first sensor, without departing from the scope of the various described examples. The first sensor and the second sensor can both be sensors and, in some cases, can be separate and different sensors.

In addition, throughout the specification, the meaning of “a”, “an”, and “the” includes plural references, and the meaning of “in” includes “in” and “on”.

Although some of the various embodiments presented herein constitute a single combination of inventive elements, it should be appreciated that the inventive subject matter is considered to include all possible combinations of the disclosed elements. As such, if one embodiment comprises elements A, B, and C, and another embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly discussed herein. Further, the transitional term “comprising” means to have as parts or members, or to be those parts or members. As used herein, the transitional term “comprising” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

Throughout the following disclosure, numerous references may be made regarding servers, services, interfaces, engines, modules, clients, peers, portals, platforms, or other systems formed from computing devices. It should be appreciated that the use of such terms is deemed to represent one or more computing devices having at least one processor (e.g., ASIC, FPGA, PLD, DSP, x86, ARM, RISC-V, ColdFire, GPU, multi-core processors, etc.) configured to execute software instructions stored on a computer readable tangible, non-transitory medium (e.g., hard drive, solid state drive, RAM, flash, ROM, etc.). For example, a server can include one or more computers operating as a web server, database server, or other type of computer server in a manner to fulfill described roles, responsibilities, or functions. One should further appreciate the disclosed computer-based algorithms, processes, methods, or other types of instruction sets can be embodied as a computer program product comprising a non-transitory, tangible computer readable medium storing the instructions that cause a processor to execute the disclosed steps. The various servers, systems, databases, or interfaces can exchange data using standardized protocols or algorithms, possibly based on HTTP, HTTPS, AES, public-private key exchanges, web service APIs, known financial transaction protocols, or other electronic information exchanging methods. Data exchanges can be conducted over a packet-switched network, a circuit-switched network, the Internet, LAN, WAN, VPN, or other type of network.

As used in the description herein and throughout the claims that follow, when a system, engine, server, device, module, or other computing element is described as being configured to perform or execute functions on data in a memory, the meaning of “configured to” or “programmed to” is defined as one or more processors or cores of the computing element being programmed by a set of software instructions stored in the memory of the computing element to execute the set of functions on target data or data objects stored in the memory.

It should be noted that any language directed to a computer should be read to include any suitable combination of computing devices or network platforms, including servers, interfaces, systems, databases, agents, peers, engines, controllers, modules, or other types of computing devices operating individually or collectively. One should appreciate the computing devices comprise a processor configured to execute software instructions stored on a tangible, non-transitory computer readable storage medium (e.g., hard drive, FPGA, PLA, solid state drive, RAM, flash, ROM, etc.). The software instructions configure or program the computing device to provide the roles, responsibilities, or other functionality as discussed below with respect to the disclosed apparatus. Further, the disclosed technologies can be embodied as a computer program product that includes a non-transitory computer readable medium storing the software instructions that causes a processor to execute the disclosed steps associated with implementations of computer-based algorithms, processes, methods, or other instructions. In some embodiments, the various servers, systems, databases, or interfaces exchange data using standardized protocols or algorithms, possibly based on HTTP, HTTPS, AES, public-private key exchanges, web service APIs, known financial transaction protocols, or other electronic information exchanging methods. Data exchanges among devices can be conducted over a packet-switched network, the Internet, LAN, WAN, VPN, or other type of packet switched network; a circuit switched network; cell switched network; or other type of network.

A LiDAR device may be positioned at various locations on an exterior surface of vehicle. For example, one exemplary location for optimal scanning performance and Field-of-View (FOV) may be on a top surface of a vehicle (e.g., an exterior surface of the roof of the vehicle). Such a top surface location may extend above the roof line of the vehicle but remain relatively close to the driver's (or another front passenger's) seating position within the vehicle. Therefore, the rooftop placement of the LiDAR device may be relatively close to a driver's/front passenger's head (and ears) such that unwanted and/or excessive acoustic noise and vibration from the LiDAR device can be transmitted through the car roof structures and be very disturbing to the driver and other vehicle passengers during vehicle operation.

A vehicle-based LiDAR device may comprise a high-speed polygon and galvo. A vehicle-based LiDAR device may include an optical core assembly comprising a high-speed polygon-motor rotating element and a galvo. For various vehicle-based applications, the polygon may rotate at speeds between about 3000-12000 revolutions per minute during the operation of the optical core assembly. At the same time, the galvo may also oscillate or rotate at very high speeds to steer light reflected by the polygon in particular directions. Because of these operational conditions, the polygon and galvo may tend to generate undesirable acoustic noises and vibrations. Furthermore, the LiDAR device may also be subject to imbalances, noises, shock displacements, vibrations, or other harsh conditions during the operation of the vehicle. One or more of the noises, shocks, vibrations, lateral wobbles, or other harsh conditions may cause displacement of the elements and/or parts of the LiDAR optical core assembly and may thus further affect the smoothness and control of the operation of the LiDAR optical core assembly. This may in turn affect the accuracy and overall performance of the LiDAR device. Thus, there is a need to eliminate or reduce the impact caused by these conditions. An isolation system as described herein may be implemented to address these concerns.

Embodiments of an isolation system for a light detection and ranging (LiDAR) optical core assembly are described below. The LiDAR optical core assembly comprises a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics. The isolation system comprises a polygon-motor base element coupled to the polygon-motor rotating element and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element. The plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.

FIG. 1 illustrates one or more exemplary LiDAR systems 110 disposed or included in a motor vehicle 100. Motor vehicle 100 can be a vehicle having any automated level. For example, motor vehicle 100 can be a partially automated vehicle, a highly automated vehicle, a fully automated vehicle, or a driverless vehicle. A partially automated vehicle can perform some driving functions without a human driver's intervention. For example, a partially automated vehicle can perform blind-spot monitoring, lane keeping and/or lane changing operations, automated emergency braking, smart cruising and/or traffic following, or the like. Certain operations of a partially automated vehicle may be limited to specific applications or driving scenarios (e.g., limited to only freeway driving). A highly automated vehicle can generally perform all operations of a partially automated vehicle but with less limitations. A highly automated vehicle can also detect its own limits in operating the vehicle and ask the driver to take over the control of the vehicle when necessary. A fully automated vehicle can perform all vehicle operations without a driver's intervention but can also detect its own limits and ask the driver to take over when necessary. A driverless vehicle can operate on its own without any driver intervention.

In typical configurations, motor vehicle 100 comprises one or more LiDAR systems 110 and 120A-F. Each of LiDAR systems 110 and 120A-F can be a scanning-based LiDAR system and/or a non-scanning LiDAR system (e.g., a flash LiDAR). A scanning-based LiDAR system scans one or more light beams in one or more directions (e.g., horizontal and vertical directions) to detect objects in a field-of-view (FOV). A non-scanning based LiDAR system transmits laser light to illuminate an FOV without scanning. For example, a flash LiDAR is a type of non-scanning based LiDAR system. A flash LiDAR can transmit laser light to simultaneously illuminate an FOV using a single light pulse or light shot.

A LiDAR system is often an essential sensor of a vehicle that is at least partially automated. In one embodiment, as shown in FIG. 1 , motor vehicle 100 may include a single LiDAR system 110 (e.g., without LiDAR systems 120A-F) disposed at the highest position of the vehicle (e.g., at the vehicle roof). Disposing LiDAR system 110 at the vehicle roof facilitates a 360-degree scanning around vehicle 100. In some other embodiments, motor vehicle 100 can include multiple LiDAR systems, including two or more of systems 110 and/or 120A-F. As shown in FIG. 1 , in one embodiment, multiple LiDAR systems 110 and/or 120A-F are attached to vehicle 100 at different locations of the vehicle. For example, LiDAR system 120A is attached to vehicle 100 at the front right corner; LiDAR system 120B is attached to vehicle 100 at the front center; LiDAR system 120C is attached to vehicle 100 at the front left corner; LiDAR system 120D is attached to vehicle 100 at the right-side rear view mirror; LiDAR system 120E is attached to vehicle 100 at the left-side rear view mirror; and/or LiDAR system 120F is attached to vehicle 100 at the back center. In some embodiments, LiDAR systems 110 and 120A-F are independent LiDAR systems having their own respective laser sources, control electronics, transmitters, receivers, and/or steering mechanisms. In other embodiments, some of LiDAR systems 110 and 120A-F can share one or more components, thereby forming a distributed sensor system. In one example, optical fibers are used to deliver laser light from a centralized laser source to all LiDAR systems. It is understood that one or more LiDAR systems can be distributed and attached to a vehicle in any desired manner and FIG. 1 only illustrates one embodiment. As another example, LiDAR systems 120D and 120E may be attached to the B-pillars of vehicle 100 instead of the rear-view mirrors. As another example, LiDAR system 120B may be attached to the windshield of vehicle 100 instead of the front bumper.

FIG. 2 is a block diagram 200 illustrating interactions between vehicle onboard LiDAR system(s) 210 and multiple other systems including a vehicle perception and planning system 220. LiDAR system(s) 210 can be mounted on or integrated to a vehicle. LiDAR system(s) 210 include sensor(s) that scan laser light to the surrounding environment to measure the distance, angle, and/or velocity of objects. Based on the scattered light that returned to LiDAR system(s) 210, it can generate sensor data (e.g., image data or 3D point cloud data) representing the perceived external environment.

LiDAR system(s) 210 can include one or more of short-range LiDAR sensors, medium-range LiDAR sensors, and long-range LiDAR sensors. A short-range LiDAR sensor measures objects located up to about 20-40 meters from the LiDAR sensor. Short-range LiDAR sensors can be used for, e.g., monitoring nearby moving objects (e.g., pedestrians crossing street in a school zone), parking assistance applications, or the like. A medium-range LiDAR sensor measures objects located up to about 100-150 meters from the LiDAR sensor. Medium-range LiDAR sensors can be used for, e.g., monitoring road intersections, assistance for merging onto or leaving a freeway, or the like. A long-range LiDAR sensor measures objects located up to about 150-300 meters. Long-range LiDAR sensors are typically used when a vehicle is travelling at high speed (e.g., on a freeway), such that the vehicle's control systems may only have a few seconds (e.g., 6-8 seconds) to respond to any situations detected by the LiDAR sensor. As shown in FIG. 2 , in one embodiment, the LiDAR sensor data can be provided to vehicle perception and planning system 220 via a communication path 213 for further processing and controlling the vehicle operations. Communication path 213 can be any wired or wireless communication links that can transfer data.

With reference still to FIG. 2 , in some embodiments, other vehicle onboard sensor(s) 230 are used to provide additional sensor data separately or together with LiDAR system(s) 210. Other vehicle onboard sensors 230 may include, for example, one or more camera(s) 232, one or more radar(s) 234, one or more ultrasonic sensor(s) 236, and/or other sensor(s) 238. Camera(s) 232 can take images and/or videos of the external environment of a vehicle. Camera(s) 232 can take, for example, high-definition (HD) videos having millions of pixels in each frame. A camera produces monochrome or color images and videos. Color information may be important in interpreting data for some situations (e.g., interpreting images of traffic lights). Color information may not be available from other sensors such as LiDAR or radar sensors. Camera(s) 232 can include one or more of narrow-focus cameras, wider-focus cameras, side-facing cameras, infrared cameras, fisheye cameras, or the like. The image and/or video data generated by camera(s) 232 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. Communication path 233 can be any wired or wireless communication links that can transfer data.

Other vehicle onboard sensors(s) 230 can also include radar sensor(s) 234. Radar sensor(s) 234 use radio waves to determine the range, angle, and velocity of objects. Radar sensor(s) 234 produce electromagnetic waves in the radio or microwave spectrum. The electromagnetic waves reflect off an object and some of the reflected waves return to the radar sensor, thereby providing information about the object's position and velocity. Radar sensor(s) 234 can include one or more of short-range radar(s), medium-range radar(s), and long-range radar(s). A short-range radar measures objects located at about 0.1-30 meters from the radar. A short-range radar is useful in detecting objects located nearby the vehicle, such as other vehicles, buildings, walls, pedestrians, bicyclists, etc. A short-range radar can be used to detect a blind spot, assist in lane changing, provide rear-end collision warning, assist in parking, provide emergency braking, or the like. A medium-range radar measures objects located at about 30-80 meters from the radar. A long-range radar measures objects located at about 80-200 meters. Medium- and/or long-range radars can be useful in, for example, traffic following, adaptive cruise control, and/or highway automatic braking. Sensor data generated by radar sensor(s) 234 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations.

Other vehicle onboard sensor(s) 230 can also include ultrasonic sensor(s) 236. Ultrasonic sensor(s) 236 use acoustic waves or pulses to measure object located external to a vehicle. The acoustic waves generated by ultrasonic sensor(s) 236 are transmitted to the surrounding environment. At least some of the transmitted waves are reflected off an object and return to the ultrasonic sensor(s) 236. Based on the return signals, a distance of the object can be calculated. Ultrasonic sensor(s) 236 can be useful in, for example, check blind spot, identify parking spots, provide lane changing assistance into traffic, or the like. Sensor data generated by ultrasonic sensor(s) 236 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations.

In some embodiments, one or more other sensor(s) 238 may be attached in a vehicle and may also generate sensor data. Other sensor(s) 238 may include, for example, global positioning systems (GPS), inertial measurement units (IMU), or the like. Sensor data generated by other sensor(s) 238 can also be provided to vehicle perception and planning system 220 via communication path 233 for further processing and controlling the vehicle operations. It is understood that communication path 233 may include one or more communication links to transfer data between the various sensor(s) 230 and vehicle perception and planning system 220.

In some embodiments, as shown in FIG. 2 , sensor data from other vehicle onboard sensor(s) 230 can be provided to vehicle onboard LiDAR system(s) 210 via communication path 231. LiDAR system(s) 210 may process the sensor data from other vehicle onboard sensor(s) 230. For example, sensor data from camera(s) 232, radar sensor(s) 234, ultrasonic sensor(s) 236, and/or other sensor(s) 238 may be correlated or fused with sensor data LiDAR system(s) 210, thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220. It is understood that other configurations may also be implemented for transmitting and processing sensor data from the various sensors (e.g., data can be transmitted to a cloud service for processing and then the processing results can be transmitted back to the vehicle perception and planning system 220).

With reference still to FIG. 2 , in some embodiments, sensors onboard other vehicle(s) 250 are used to provide additional sensor data separately or together with LiDAR system(s) 210. For example, two or more nearby vehicles may have their own respective LiDAR sensor(s), camera(s), radar sensor(s), ultrasonic sensor(s), etc. Nearby vehicles can communicate and share sensor data with one another. Communications between vehicles are also referred to as V2V (vehicle to vehicle) communications. For example, as shown in FIG. 2 , sensor data generated by other vehicle(s) 250 can be communicated to vehicle perception and planning system 220 and/or vehicle onboard LiDAR system(s) 210, via communication path 253 and/or communication path 251, respectively. Communication paths 253 and 251 can be any wired or wireless communication links that can transfer data.

Sharing sensor data facilitates a better perception of the environment external to the vehicles. For instance, a first vehicle may not sense a pedestrian that is a behind a second vehicle but is approaching the first vehicle. The second vehicle may share the sensor data related to this pedestrian with the first vehicle such that the first vehicle can have additional reaction time to avoid collision with the pedestrian. In some embodiments, similar to data generated by sensor(s) 230, data generated by sensors onboard other vehicle(s) 250 may be correlated or fused with sensor data generated by LiDAR system(s) 210, thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220.

In some embodiments, intelligent infrastructure system(s) 240 are used to provide sensor data separately or together with LiDAR system(s) 210. Certain infrastructures may be configured to communicate with a vehicle to convey information and vice versa. Communications between a vehicle and infrastructures are generally referred to as V2I (vehicle to infrastructure) communications. For example, intelligent infrastructure system(s) 240 may include an intelligent traffic light that can convey its status to an approaching vehicle in a message such as “changing to yellow in 5 seconds.” Intelligent infrastructure system(s) 240 may also include its own LiDAR system mounted near an intersection such that it can convey traffic monitoring information to a vehicle. For example, a left-turning vehicle at an intersection may not have sufficient sensing capabilities because some of its own sensors may be blocked by traffics in the opposite direction. In such a situation, sensors of intelligent infrastructure system(s) 240 can provide useful, and sometimes vital, data to the left-turning vehicle. Such data may include, for example, traffic conditions, information of objects in the direction the vehicle is turning to, traffic light status and predictions, or the like. These sensor data generated by intelligent infrastructure system(s) 240 can be provided to vehicle perception and planning system 220 and/or vehicle onboard LiDAR system(s) 210, via communication paths 243 and/or 241, respectively. Communication paths 243 and/or 241 can include any wired or wireless communication links that can transfer data. For example, sensor data from intelligent infrastructure system(s) 240 may be transmitted to LiDAR system(s) 210 and correlated or fused with sensor data generated by LiDAR system(s) 210, thereby at least partially offloading the sensor fusion process performed by vehicle perception and planning system 220. V2V and V2I communications described above are examples of vehicle-to-X (V2X) communications, where the “X” represents any other devices, systems, sensors, infrastructure, or the like that can share data with a vehicle.

With reference still to FIG. 2 , via various communication paths, vehicle perception and planning system 220 receives sensor data from one or more of LiDAR system(s) 210, other vehicle onboard sensor(s) 230, other vehicle(s) 250, and/or intelligent infrastructure system(s) 240. In some embodiments, different types of sensor data are correlated and/or integrated by a sensor fusion sub-system 222. For example, sensor fusion sub-system 222 can generate a 360-degree model using multiple images or videos captured by multiple cameras disposed at different positions of the vehicle. Sensor fusion sub-system 222 obtains sensor data from different types of sensors and uses the combined data to perceive the environment more accurately. For example, a vehicle onboard camera 232 may not capture a clear image because it is facing the sun or a light source (e.g., another vehicle's headlight during nighttime) directly. A LiDAR system 210 may not be affected as much and therefore sensor fusion sub-system 222 can combine sensor data provided by both camera 232 and LiDAR system 210, and use the sensor data provided by LiDAR system 210 to compensate the unclear image captured by camera 232. As another example, in a rainy or foggy weather, a radar sensor 234 may work better than a camera 232 or a LiDAR system 210. Accordingly, sensor fusion sub-system 222 may use sensor data provided by the radar sensor 234 to compensate the sensor data provided by camera 232 or LiDAR system 210.

In other examples, sensor data generated by other vehicle onboard sensor(s) 230 may have a lower resolution (e.g., radar sensor data) and thus may need to be correlated and confirmed by LiDAR system(s) 210, which usually has a higher resolution. For example, a sewage cover (also referred to as a manhole cover) may be detected by radar sensor 234 as an object towards which a vehicle is approaching. Due to the low-resolution nature of radar sensor 234, vehicle perception and planning system 220 may not be able to determine whether the object is an obstacle that the vehicle needs to avoid. High-resolution sensor data generated by LiDAR system(s) 210 thus can be used to correlated and confirm that the object is a sewage cover and causes no harm to the vehicle.

Vehicle perception and planning system 220 further comprises an object classifier 223. Using raw sensor data and/or correlated/fused data provided by sensor fusion sub-system 222, object classifier 223 can detect and classify the objects and estimate the positions of the objects. In some embodiments, object classifier 233 can use machine-learning based techniques to detect and classify objects. Examples of the machine-learning based techniques include utilizing algorithms such as region-based convolutional neural networks (R-CNN), Fast R-CNN, Faster R-CNN, histogram of oriented gradients (HOG), region-based fully convolutional network (R-FCN), single shot detector (SSD), spatial pyramid pooling (SPP-net), and/or You Only Look Once (Yolo).

Vehicle perception and planning system 220 further comprises a road detection sub-system 224. Road detection sub-system 224 localizes the road and identifies objects and/or markings on the road. For example, based on raw or fused sensor data provided by radar sensor(s) 234, camera(s) 232, and/or LiDAR system(s) 210, road detection sub-system 224 can build a 3D model of the road based on machine-learning techniques (e.g., pattern recognition algorithms for identifying lanes). Using the 3D model of the road, road detection sub-system 224 can identify objects (e.g., obstacles or debris on the road) and/or markings on the road (e.g., lane lines, turning marks, crosswalk marks, or the like).

Vehicle perception and planning system 220 further comprises a localization and vehicle posture sub-system 225. Based on raw or fused sensor data, localization and vehicle posture sub-system 225 can determine position of the vehicle and the vehicle's posture. For example, using sensor data from LiDAR system(s) 210, camera(s) 232, and/or GPS data, localization and vehicle posture sub-system 225 can determine an accurate position of the vehicle on the road and the vehicle's six degrees of freedom (e.g., whether the vehicle is moving forward or backward, up or down, and left or right). In some embodiments, high-definition (HD) maps are used for vehicle localization. HD maps can provide highly detailed, three-dimensional, computerized maps that pinpoint a vehicle's location. For instance, using the HD maps, localization and vehicle posture sub-system 225 can determine precisely the vehicle's current position (e.g., which lane of the road the vehicle is currently in, how close it is to a curb or a sidewalk) and predict vehicle's future positions.

Vehicle perception and planning system 220 further comprises obstacle predictor 226. Objects identified by object classifier 223 can be stationary (e.g., a light pole, a road sign) or dynamic (e.g., a moving pedestrian, bicycle, another car). For moving objects, predicting their moving path or future positions can be important to avoid collision. Obstacle predictor 226 can predict an obstacle trajectory and/or warn the driver or the vehicle planning sub-system 228 about a potential collision. For example, if there is a high likelihood that the obstacle's trajectory intersects with the vehicle's current moving path, obstacle predictor 226 can generate such a warning. Obstacle predictor 226 can use a variety of techniques for making such a prediction. Such techniques include, for example, constant velocity or acceleration models, constant turn rate and velocity/acceleration models, Kalman Filter and Extended Kalman Filter based models, recurrent neural network (RNN) based models, long short-term memory (LSTM) neural network-based models, encoder-decoder RNN models, or the like.

With reference still to FIG. 2 , in some embodiments, vehicle perception and planning system 220 further comprises vehicle planning sub-system 228. Vehicle planning sub-system 228 can include a route planner, a driving behaviors planner, and a motion planner. The route planner can plan the route of a vehicle based on the vehicle's current location data, target location data, traffic information, etc. The driving behavior planner adjusts the timing and planned movement based on how other objects might move, using the obstacle prediction results provided by obstacle predictor 226. The motion planner determines the specific operations the vehicle needs to follow. The planning results are then communicated to vehicle control system 280 via vehicle interface 270. The communication can be performed through communication paths 223 and 271, which include any wired or wireless communication links that can transfer data.

Vehicle control system 280 controls the vehicle's steering mechanism, throttle, brake, etc., to operate the vehicle according to the planned route and movement. Vehicle perception and planning system 220 may further comprise a user interface 260, which provides a user (e.g., a driver) access to vehicle control system 280 to, for example, override or take over control of the vehicle when necessary. User interface 260 can communicate with vehicle perception and planning system 220, for example, to obtain and display raw or fused sensor data, identified objects, vehicle's location/posture, etc. These displayed data can help a user to better operate the vehicle. User interface 260 can communicate with vehicle perception and planning system 220 and/or vehicle control system 280 via communication paths 221 and 261 respectively, which include any wired or wireless communication links that can transfer data. It is understood that the various systems, sensors, communication links, and interfaces in FIG. 2 can be configured in any desired manner and not limited to the configuration shown in FIG. 2 .

FIG. 3 is a block diagram illustrating an exemplary LiDAR system 300. LiDAR system 300 can be used to implement LiDAR system 110, 120A-F, and/or 210 shown in FIGS. 1 and 2 . In one embodiment, LiDAR system 300 comprises a laser source 310, a transmitter 320, an optical receiver and light detector 330, a steering system 340, and a control circuitry 350. These components are coupled together using communications paths 312, 314, 322, 332, 343, 352, and 362. These communications paths include communication links (wired or wireless, bidirectional or unidirectional) among the various LiDAR system components, but need not be physical components themselves. While the communications paths can be implemented by one or more electrical wires, buses, or optical fibers, the communication paths can also be wireless channels or free-space optical paths so that no physical communication medium is present. For example, in one embodiment of LiDAR system 300, communication path 314 between laser source 310 and transmitter 320 may be implemented using one or more optical fibers. Communication paths 332 and 352 may represent optical paths implemented using free space optical components and/or optical fibers. And communication paths 312, 322, 342, and 362 may be implemented using one or more electrical wires that carry electrical signals. The communications paths can also include one or more of the above types of communication mediums (e.g., they can include an optical fiber and a free-space optical component, or include one or more optical fibers and one or more electrical wires).

LiDAR system 300 can also include other components not depicted in FIG. 3 , such as power buses, power supplies, LED indicators, switches, etc. Additionally, other communication connections among components may be present, such as a direct connection between light source 310 and optical receiver and light detector 330 to provide a reference signal so that the time from when a light pulse is transmitted until a return light pulse is detected can be accurately measured.

Laser source 310 outputs laser light for illuminating objects in a field of view (FOV). Laser source 310 can be, for example, a semiconductor-based laser (e.g., a diode laser) and/or a fiber-based laser. A semiconductor-based laser can be, for example, an edge emitting laser (EEL), a vertical cavity surface emitting laser (VCSEL), or the like. A fiber-based laser is a laser in which the active gain medium is an optical fiber doped with rare-earth elements such as erbium, ytterbium, neodymium, dysprosium, praseodymium, thulium and/or holmium. In some embodiments, a fiber laser is based on double-clad fibers, in which the gain medium forms the core of the fiber surrounded by two layers of cladding. The double-clad fiber allows the core to be pumped with a high-power beam, thereby enabling the laser source to be a high-power fiber laser source.

In some embodiments, laser source 310 comprises a master oscillator (also referred to as a seed laser) and power amplifier (MOPA). The power amplifier amplifies the output power of the seed laser. The power amplifier can be a fiber amplifier, a bulk amplifier, or a semiconductor optical amplifier. The seed laser can be a diode laser (e.g., a Fabry-Perot cavity laser, a distributed feedback laser), a solid-state bulk laser, or a tunable external-cavity diode laser. In some embodiments, laser source 310 can be an optically pumped microchip laser. Microchip lasers are alignment-free monolithic solid-state lasers where the laser crystal is directly contacted with the end mirrors of the laser resonator. A microchip laser is typically pumped with a laser diode (directly or using a fiber) to obtain the desired output power. A microchip laser can be based on neodymium-doped yttrium aluminum garnet (Y₃Al₅O₁₂) laser crystals (i.e., Nd:YAG), or neodymium-doped vanadate (i.e., ND:YVO₄) laser crystals.

FIG. 4 is a block diagram illustrating an exemplary fiber-based laser source 400 having a seed laser and one or more pumps (e.g., laser diodes) for pumping desired output power. Fiber-based laser source 400 is an example of laser source 310 depicted in FIG. 3 . In some embodiments, fiber-based laser source 400 comprises a seed laser 402 to generate initial light pulses of one or more wavelengths (e.g., 1550 nm), which are provided to a wavelength-division multiplexor (WDM) 404 via an optical fiber 403. Fiber-based laser source 400 further comprises a pump 406 for providing laser power (e.g., of a different wavelength, such as 980 nm) to WDM 404 via an optical fiber 405. WDM 404 multiplexes the light pulses provided by seed laser 402 and the laser power provided by pump 406 onto a single optical fiber 407. The output of WDM 404 can then be provided to one or more pre-amplifier(s) 408 via optical fiber 407. Pre-amplifier(s) 408 can be optical amplifier(s) that amplify optical signals (e.g., with about 20-30 dB gain). In some embodiments, pre-amplifier(s) 408 are low noise amplifiers. Pre-amplifier(s) 408 output to a combiner 410 via an optical fiber 409. Combiner 410 combines the output laser light of pre-amplifier(s) 408 with the laser power provided by pump 412 via an optical fiber 411. Combiner 410 can combine optical signals having the same wavelength or different wavelengths. One example of a combiner is a WDM. Combiner 410 provides pulses to a booster amplifier 414, which produces output light pulses via optical fiber 410. The booster amplifier 414 provides further amplification of the optical signals. The outputted light pulses can then be transmitted to transmitter 320 and/or steering mechanism 340 (shown in FIG. 3 ). It is understood that FIG. 4 illustrates one exemplary configuration of fiber-based laser source 400. Laser source 400 can have many other configurations using different combinations of one or more components shown in FIG. 4 and/or other components not shown in FIG. 4 (e.g., other components such as power supplies, lens, filters, splitters, combiners, etc.).

In some variations, fiber-based laser source 400 can be controlled (e.g., by control circuitry 350) to produce pulses of different amplitudes based on the fiber gain profile of the fiber used in fiber-based laser source 400. Communication path 312 couples fiber-based laser source 400 to control circuitry 350 (shown in FIG. 3 ) so that components of fiber-based laser source 400 can be controlled by or otherwise communicate with control circuitry 350. Alternatively, fiber-based laser source 400 may include its own dedicated controller. Instead of control circuitry 350 communicating directly with components of fiber-based laser source 400, a dedicated controller of fiber-based laser source 400 communicates with control circuitry 350 and controls and/or communicates with the components of fiber-based light source 400. Fiber-based light source 400 can also include other components not shown, such as one or more power connectors, power supplies, and/or power lines.

Referencing FIG. 3 , typical operating wavelengths of laser source 310 comprise, for example, about 850 nm, about 905 nm, about 940 nm, about 1064 nm, and about 1550 nm. The upper limit of maximum usable laser power is set by the U.S. FDA (U.S. Food and Drug Administration) regulations. The optical power limit at 1550 nm wavelength is much higher than those of the other aforementioned wavelengths. Further, at 1550 nm, the optical power loss in a fiber is low. There characteristics of the 1550 nm wavelength make it more beneficial for long-range LiDAR applications. The amount of optical power output from laser source 310 can be characterized by its peak power, average power, and the pulse energy. The peak power is the ratio of pulse energy to the width of the pulse (e.g., full width at half maximum or FWHM). Thus, a smaller pulse width can provide a larger peak power for a fixed amount of pulse energy. A pulse width can be in the range of nanosecond or picosecond. The average power is the product of the energy of the pulse and the pulse repetition rate (PRR). As described in more detail below, the PRR represents the frequency of the pulsed laser light. The PRR typically corresponds to the maximum range that a LiDAR system can measure. Laser source 310 can be configured to produce pulses at high PRR to meet the desired number of data points in a point cloud generated by the LiDAR system. Laser source 310 can also be configured to produce pulses at medium or low PRR to meet the desired maximum detection distance. Wall plug efficiency (WPE) is another factor to evaluate the total power consumption, which may be a key indicator in evaluating the laser efficiency. For example, as shown in FIG. 1 , multiple LiDAR systems may be attached to a vehicle, which may be an electrical-powered vehicle or a vehicle otherwise having limited fuel or battery power supply. Therefore, high WPE and intelligent ways to use laser power are often among the important considerations when selecting and configuring laser source 310 and/or designing laser delivery systems for vehicle-mounted LiDAR applications.

It is understood that the above descriptions provide non-limiting examples of a laser source 310. Laser source 310 can be configured to include many other types of light sources (e.g., laser diodes, short-cavity fiber lasers, solid-state lasers, and/or tunable external cavity diode lasers) that are configured to generate one or more light signals at various wavelengths. In some examples, light source 310 comprises amplifiers (e.g., pre-amplifiers and/or booster amplifiers), which can be a doped optical fiber amplifier, a solid-state bulk amplifier, and/or a semiconductor optical amplifier. The amplifiers are configured to receive and amplify light signals with desired gains.

With reference back to FIG. 3 , the LiDAR system 300 further comprises a transmitter 320. Laser source 310 provides laser light (e.g., in the form of a laser beam) to transmitter 320. The laser light provided by laser source 310 can be amplified laser light with a predetermined or controlled wavelength, pulse repetition rate, and/or power level. Transmitter 320 receives the laser light from laser source 310 and transmits the laser light to steering mechanism 340 with low divergence. In some embodiments, transmitter 320 can include, for example, optical components (e.g., lens, fibers, mirrors, etc.) for transmitting laser beams to a field-of-view (FOV) directly or via steering mechanism 340. While FIG. 3 illustrates transmitter 320 and steering mechanism 340 as separate components, they may be combined or integrated as one system in some embodiments. Steering mechanism 340 is described in more detail below.

Laser beams provided by laser source 310 may diverge as they travel to transmitter 320. Therefore, transmitter 320 often comprises a collimating lens configured to collect the diverging laser beams and produce more parallel optical beams with reduced or minimum divergence. The collimated optical beams can then be further directed through various optics such as mirrors and lens. A collimating lens may be, for example, a single plano-convex lens or a lens group. The collimating lens can be configured to achieve any desired properties such as the beam diameter, divergence, numerical aperture, focal length, or the like. A beam propagation ratio or beam quality factor (also referred to as the M² factor) is used for measurement of laser beam quality. In many LiDAR applications, it is important to have good laser beam quality in the generated transmitting laser beam. The M² factor represents a degree of variation of a beam from an ideal Gaussian beam. Thus, the M² factor reflects how well a collimated laser beam can be focused on a small spot, or how well a divergent laser beam can be collimated. Therefore, laser source 310 and/or transmitter 320 can be configured to meet, for example, a scan resolution requirement while maintaining the desired M² factor.

One or more of the light beams provided by transmitter 320 are scanned by steering mechanism 340 to a FOV. Steering mechanism 340 scans light beams in multiple dimensions (e.g., in both the horizontal and vertical dimension) to facilitate LiDAR system 300 to map the environment by generating a 3D point cloud. Steering mechanism 340 will be described in more detail below. The laser light scanned to an FOV may be scattered or reflected by an object in the FOV. At least a portion of the scattered or reflected light returns to LiDAR system 300. FIG. 3 further illustrates an optical receiver and light detector 330 configured to receive the return light. Optical receiver and light detector 330 comprises an optical receiver that is configured to collect the return light from the FOV. The optical receiver can include optics (e.g., lens, fibers, mirrors, etc.) for receiving, redirecting, focus, amplifying, and/or filtering return light from the FOV. For example, the optical receiver often includes a collection lens (e.g., a single plano-convex lens or a lens group) to collect and/or focus the collected return light onto a light detector.

A light detector detects the return light focused by the optical receiver and generates current and/or voltage signals proportional to the incident intensity of the return light. Based on such current and/or voltage signals, the depth information of the object in the FOV can be derived. One exemplary method for deriving such depth information is based on the direct TOF (time of flight), which is described in more detail below. A light detector may be characterized by its detection sensitivity, quantum efficiency, detector bandwidth, linearity, signal to noise ratio (SNR), overload resistance, interference immunity, etc. Based on the applications, the light detector can be configured or customized to have any desired characteristics. For example, optical receiver and light detector 330 can be configured such that the light detector has a large dynamic range while having a good linearity. The light detector linearity indicates the detector's capability of maintaining linear relationship between input optical signal power and the detector's output. A detector having good linearity can maintain a linear relationship over a large dynamic input optical signal range.

To achieve desired detector characteristics, configurations or customizations can be made to the light detector's structure and/or the detector's material system. Various detector structure can be used for a light detector. For example, a light detector structure can be a PIN based structure, which has a undoped intrinsic semiconductor region (i.e., an “i” region) between a p-type semiconductor and an n-type semiconductor region. Other light detector structures comprise, for example, a APD (avalanche photodiode) based structure, a PMT (photomultiplier tube) based structure, a SiPM (Silicon photomultiplier) based structure, a SPAD (single-photon avalanche diode) base structure, and/or quantum wires. For material systems used in a light detector, Si, InGaAs, and/or Si/Ge based materials can be used. It is understood that many other detector structures and/or material systems can be used in optical receiver and light detector 330.

A light detector (e.g., an APD based detector) may have an internal gain such that the input signal is amplified when generating an output signal. However, noise may also be amplified due to the light detector's internal gain. Common types of noise include signal shot noise, dark current shot noise, thermal noise, and amplifier noise (TIA). In some embodiments, optical receiver and light detector 330 may include a pre-amplifier that is a low noise amplifier (LNA). In some embodiments, the pre-amplifier may also include a TIA-transimpedance amplifier, which converts a current signal to a voltage signal. For a linear detector system, input equivalent noise or noise equivalent power (NEP) measures how sensitive the light detector is to weak signals. Therefore, they can be used as indicators of the overall system performance. For example, the NEP of a light detector specifies the power of the weakest signal that can be detected and therefore it in turn specifies the maximum range of a LiDAR system. It is understood that various light detector optimization techniques can be used to meet the requirement of LiDAR system 300. Such optimization techniques may include selecting different detector structures, materials, and/or implement signal processing techniques (e.g., filtering, noise reduction, amplification, or the like). For example, in addition to or instead of using direct detection of return signals (e.g., by using TOF), coherent detection can also be used for a light detector. Coherent detection allows for detecting amplitude and phase information of the received light by interfering the received light with a local oscillator. Coherent detection can improve detection sensitivity and noise immunity.

FIG. 3 further illustrates that LiDAR system 300 comprises steering mechanism 340. As described above, steering mechanism 340 directs light beams from transmitter 320 to scan an FOV in multiple dimensions. A steering mechanism is referred to as a raster mechanism or a scanning mechanism. Scanning light beams in multiple directions (e.g., in both the horizontal and vertical directions) facilitates a LiDAR system to map the environment by generating an image or a 3D point cloud. A steering mechanism can be based on mechanical scanning and/or solid-state scanning. Mechanical scanning uses rotating mirrors to steer the laser beam or physically rotate the LiDAR transmitter and receiver (collectively referred to as transceiver) to scan the laser beam. Solid-state scanning directs the laser beam to various positions through the FOV without mechanically moving any macroscopic components such as the transceiver. Solid-state scanning mechanisms include, for example, optical phased arrays based steering and flash LiDAR based steering. In some embodiments, because solid-state scanning mechanisms do not physically move macroscopic components, the steering performed by a solid-state scanning mechanism may be referred to as effective steering. A LiDAR system using solid-state scanning may also be referred to as a non-mechanical scanning or simply non-scanning LiDAR system (a flash LiDAR system is an exemplary non-scanning LiDAR system).

Steering mechanism 340 can be used with the transceiver (e.g., transmitter 320 and optical receiver and light detector 330) to scan the FOV for generating an image or a 3D point cloud. As an example, to implement steering mechanism 340, a two-dimensional mechanical scanner can be used with a single-point or several single-point transceivers. A single-point transceiver transmits a single light beam or a small number of light beams (e.g., 2-8 beams) to the steering mechanism. A two-dimensional mechanical steering mechanism comprises, for example, polygon mirror(s), oscillating mirror(s), rotating prism(s), rotating tilt mirror surface(s), or a combination thereof. In some embodiments, steering mechanism 340 may include non-mechanical steering mechanism(s) such as solid-state steering mechanism(s). For example, steering mechanism 340 can be based on tuning wavelength of the laser light combined with refraction effect, and/or based on reconfigurable grating/phase array. In some embodiments, steering mechanism 340 can use a single scanning device to achieve two-dimensional scanning or two devices combined to realize two-dimensional scanning.

As another example, to implement steering mechanism 340, a one-dimensional mechanical scanner can be used with an array or a large number of single-point transceivers. Specifically, the transceiver array can be mounted on a rotating platform to achieve 360-degree horizontal field of view. Alternatively, a static transceiver array can be combined with the one-dimensional mechanical scanner. A one-dimensional mechanical scanner comprises polygon mirror(s), oscillating mirror(s), rotating prism(s), rotating tilt mirror surface(s) for obtaining a forward-looking horizontal field of view. Steering mechanisms using mechanical scanners can provide robustness and reliability in high volume production for automotive applications.

As another example, to implement steering mechanism 340, a two-dimensional transceiver can be used to generate a scan image or a 3D point cloud directly. In some embodiments, a stitching or micro shift method can be used to improve the resolution of the scan image or the field of view being scanned. For example, using a two-dimensional transceiver, signals generated at one direction (e.g., the horizontal direction) and signals generated at the other direction (e.g., the vertical direction) may be integrated, interleaved, and/or matched to generate a higher or full resolution image or 3D point cloud representing the scanned FOV.

Some implementations of steering mechanism 340 comprise one or more optical redirection elements (e.g., mirrors or lens) that steer return light signals (e.g., by rotating, vibrating, or directing) along a receive path to direct the return light signals to optical receiver and light detector 330. The optical redirection elements that direct light signals along the transmitting and receiving paths may be the same components (e.g., shared), separate components (e.g., dedicated), and/or a combination of shared and separate components. This means that in some cases the transmitting and receiving paths are different although they may partially overlap (or in some cases, substantially overlap).

With reference still to FIG. 3 , LiDAR system 300 further comprises control circuitry 350. Control circuitry 350 can be configured and/or programmed to control various parts of the LiDAR system 300 and/or to perform signal processing. In a typical system, control circuitry 350 can be configured and/or programmed to perform one or more control operations including, for example, controlling laser source 310 to obtain desired laser pulse timing, repetition rate, and power; controlling steering mechanism 340 (e.g., controlling the speed, direction, and/or other parameters) to scan the FOV and maintain pixel registration/alignment; controlling optical receiver and light detector 330 (e.g., controlling the sensitivity, noise reduction, filtering, and/or other parameters) such that it is an optimal state; and monitoring overall system health/status for functional safety.

Control circuitry 350 can also be configured and/or programmed to perform signal processing to the raw data generated by optical receiver and light detector 330 to derive distance and reflectance information, and perform data packaging and communication to vehicle perception and planning system 220 (shown in FIG. 2 ). For example, control circuitry 350 determines the time it takes from transmitting a light pulse until a corresponding return light pulse is received; determines when a return light pulse is not received for a transmitted light pulse; determines the direction (e.g., horizontal and/or vertical information) for a transmitted/return light pulse; determines the estimated range in a particular direction; and/or determines any other type of data relevant to LiDAR system 300.

LiDAR system 300 can be disposed in a vehicle, which may operate in many different environments including hot or cold weather, rough road conditions that may cause intense vibration, high or low humidifies, dusty areas, etc. Therefore, in some embodiments, optical and/or electronic components of LiDAR system 300 (e.g., optics in transmitter 320, optical receiver and light detector 330, and steering mechanism 340) are disposed or configured in such a manner to maintain long term mechanical and optical stability. For example, components in LiDAR system 300 may be secured and sealed such that they can operate under all conditions a vehicle may encounter. As an example, an anti-moisture coating and/or hermetic sealing may be applied to optical components of transmitter 320, optical receiver and light detector 330, and steering mechanism 340 (and other components that are susceptible to moisture). As another example, housing(s), enclosure(s), and/or window can be used in LiDAR system 300 for providing desired characteristics such as hardness, ingress protection (IP) rating, self-cleaning capability, resistance to chemical and resistance to impact, or the like. In addition, efficient and economical methodologies for assembling LiDAR system 300 may be used to meet the LiDAR operating requirements while keeping the cost low.

It is understood by a person of ordinary skill in the art that FIG. 3 and the above descriptions are for illustrative purposes only, and a LiDAR system can include other functional units, blocks, or segments, and can include variations or combinations of these above functional units, blocks, or segments. For example, LiDAR system 300 can also include other components not depicted in FIG. 3 , such as power buses, power supplies, LED indicators, switches, etc. Additionally, other connections among components may be present, such as a direct connection between light source 310 and optical receiver and light detector 330 so that light detector 330 can accurately measure the time from when light source 310 transmits a light pulse until light detector 330 detects a return light pulse.

These components shown in FIG. 3 are coupled together using communications paths 312, 314, 322, 332, 342, 352, and 362. These communications paths represent communication (bidirectional or unidirectional) among the various LiDAR system components but need not be physical components themselves. While the communications paths can be implemented by one or more electrical wires, busses, or optical fibers, the communication paths can also be wireless channels or open-air optical paths so that no physical communication medium is present. For example, in one exemplary LiDAR system, communication path 314 includes one or more optical fibers; communication path 352 represents an optical path; and communication paths 312, 322, 342, and 362 are all electrical wires that carry electrical signals. The communication paths can also include more than one of the above types of communication mediums (e.g., they can include an optical fiber and an optical path, or one or more optical fibers and one or more electrical wires).

As described above, some LiDAR systems use the time-of-flight (TOF) of light signals (e.g., light pulses) to determine the distance to objects in a light path. For example, with reference to FIG. 5A, an exemplary LiDAR system 500 includes a laser light source (e.g., a fiber laser), a steering system (e.g., a system of one or more moving mirrors), and a light detector (e.g., a photon detector with one or more optics). LiDAR system 500 can be implemented using, for example, LiDAR system 300 described above. LiDAR system 500 transmits a light pulse 502 along light path 504 as determined by the steering system of LiDAR system 500. In the depicted example, light pulse 502, which is generated by the laser light source, is a short pulse of laser light. Further, the signal steering system of the LiDAR system 500 is a pulsed-signal steering system. However, it should be appreciated that LiDAR systems can operate by generating, transmitting, and detecting light signals that are not pulsed and derive ranges to an object in the surrounding environment using techniques other than time-of-flight. For example, some LiDAR systems use frequency modulated continuous waves (i.e., “FMCW”). It should be further appreciated that any of the techniques described herein with respect to time-of-flight based systems that use pulsed signals also may be applicable to LiDAR systems that do not use one or both of these techniques.

Referring back to FIG. 5A (e.g., illustrating a time-of-flight LiDAR system that uses light pulses), when light pulse 502 reaches object 506, light pulse 502 scatters or reflects to generate a return light pulse 508. Return light pulse 508 may return to system 500 along light path 510. The time from when transmitted light pulse 502 leaves LiDAR system 500 to when return light pulse 508 arrives back at LiDAR system 500 can be measured (e.g., by a processor or other electronics, such as control circuitry 350, within the LiDAR system). This time-of-flight combined with the knowledge of the speed of light can be used to determine the range/distance from LiDAR system 500 to the portion of object 506 where light pulse 502 scattered or reflected.

By directing many light pulses, as depicted in FIG. 5B, LiDAR system 500 scans the external environment (e.g., by directing light pulses 502, 522, 526, 530 along light paths 504, 524, 528, 532, respectively). As depicted in FIG. 5C, LiDAR system 500 receives return light pulses 508, 542, 548 (which correspond to transmitted light pulses 502, 522, 530, respectively). Return light pulses 508, 542, and 548 are generated by scattering or reflecting the transmitted light pulses by one of objects 506 and 514. Return light pulses 508, 542, and 548 may return to LiDAR system 500 along light paths 510, 544, and 546, respectively. Based on the direction of the transmitted light pulses (as determined by LiDAR system 500) as well as the calculated range from LiDAR system 500 to the portion of objects that scatter or reflect the light pulses (e.g., the portions of objects 506 and 514), the external environment within the detectable range (e.g., the field of view between path 504 and 532, inclusively) can be precisely mapped or plotted (e.g., by generating a 3D point cloud or images).

If a corresponding light pulse is not received for a particular transmitted light pulse, then it may be determined that there are no objects within a detectable range of LiDAR system 500 (e.g., an object is beyond the maximum scanning distance of LiDAR system 500). For example, in FIG. 5B, light pulse 526 may not have a corresponding return light pulse (as illustrated in FIG. 5C) because light pulse 526 may not produce a scattering event along its transmission path 528 within the predetermined detection range. LiDAR system 500, or an external system in communication with LiDAR system 500 (e.g., a cloud system or service), can interpret the lack of return light pulse as no object being disposed along light path 528 within the detectable range of LiDAR system 500.

In FIG. 5B, light pulses 502, 522, 526, and 530 can be transmitted in any order, serially, in parallel, or based on other timings with respect to each other. Additionally, while FIG. 5B depicts transmitted light pulses as being directed in one dimension or one plane (e.g., the plane of the paper), LiDAR system 500 can also direct transmitted light pulses along other dimension(s) or plane(s). For example, LiDAR system 500 can also direct transmitted light pulses in a dimension or plane that is perpendicular to the dimension or plane shown in FIG. 5B, thereby forming a 2-dimensional transmission of the light pulses. This 2-dimensional transmission of the light pulses can be point-by-point, line-by-line, all at once, or in some other manner. A point cloud or image from a 1-dimensional transmission of light pulses (e.g., a single horizontal line) can generate 2-dimensional data (e.g., (1) data from the horizontal transmission direction and (2) the range or distance to objects). Similarly, a point cloud or image from a 2-dimensional transmission of light pulses can generate 3-dimensional data (e.g., (1) data from the horizontal transmission direction, (2) data from the vertical transmission direction, and (3) the range or distance to objects). In general, a LiDAR system performing an n-dimensional transmission of light pulses generates (n+1) dimensional data. This is because the LiDAR system can measure the depth of an object or the range/distance to the object, which provides the extra dimension of data. Therefore, a 2D scanning by a LiDAR system can generate a 3D point cloud for mapping the external environment of the LiDAR system.

The density of a point cloud refers to the number of measurements (data points) per area performed by the LiDAR system. A point cloud density relates to the LiDAR scanning resolution. Typically, a larger point cloud density, and therefore a higher resolution, is desired at least for the region of interest (ROI). The density of points in a point cloud or image generated by a LiDAR system is equal to the number of pulses divided by the field of view. In some embodiments, the field of view can be fixed. Therefore, to increase the density of points generated by one set of transmission-receiving optics (or transceiver optics), the LiDAR system may need to generate a pulse more frequently. In other words, a light source with a higher pulse repetition rate (PRR) is needed. On the other hand, by generating and transmitting pulses more frequently, the farthest distance that the LiDAR system can detect may be limited. For example, if a return signal from a distant object is received after the system transmits the next pulse, the return signals may be detected in a different order than the order in which the corresponding signals are transmitted, thereby causing ambiguity if the system cannot correctly correlate the return signals with the transmitted signals.

To illustrate, consider an exemplary LiDAR system that can transmit laser pulses with a repetition rate between 500 kHz and 1 MHz. Based on the time it takes for a pulse to return to the LiDAR system and to avoid mix-up of return pulses from consecutive pulses in a conventional LiDAR design, the farthest distance the LiDAR system can detect may be 300 meters and 150 meters for 500 kHz and 1 MHz, respectively. The density of points of a LiDAR system with 500 kHz repetition rate is half of that with 1 MHz. Thus, this example demonstrates that, if the system cannot correctly correlate return signals that arrive out of order, increasing the repetition rate from 500 kHz to 1 MHz (and thus improving the density of points of the system) may reduce the detection range of the system. Various techniques are used to mitigate the tradeoff between higher PRR and limited detection range. For example, multiple wavelengths can be used for detecting objects in different ranges. Optical and/or signal processing techniques are also used to correlate between transmitted and return light signals.

Various systems, apparatus, and methods described herein may be implemented using digital circuitry, or using one or more computers using well-known computer processors, memory units, storage devices, computer software, and other components. Typically, a computer includes a processor for executing instructions and one or more memories for storing instructions and data. A computer may also include, or be coupled to, one or more mass storage devices, such as one or more magnetic disks, internal hard disks and removable disks, magneto-optical disks, optical disks, etc.

Various systems, apparatus, and methods described herein may be implemented using computers operating in a client-server relationship. Typically, in such a system, the client computers are located remotely from the server computers and interact via a network. The client-server relationship may be defined and controlled by computer programs running on the respective client and server computers. Examples of client computers can include desktop computers, workstations, portable computers, cellular smartphones, tablets, or other types of computing devices.

Various systems, apparatus, and methods described herein may be implemented using a computer program product tangibly embodied in an information carrier, e.g., in a non-transitory machine-readable storage device, for execution by a programmable processor; and the method processes and steps described herein may be implemented using one or more computer programs that are executable by such a processor. A computer program is a set of computer program instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

A high-level block diagram of an exemplary apparatus that may be used to implement systems, apparatus and methods described herein is illustrated in FIG. 6 . Apparatus 600 comprises a processor 610 operatively coupled to a persistent storage device 620 and a main memory device 630. Processor 610 controls the overall operation of apparatus 600 by executing computer program instructions that define such operations. The computer program instructions may be stored in persistent storage device 620, or other computer-readable medium, and loaded into main memory device 630 when execution of the computer program instructions is desired. For example, processor 610 may be used to implement one or more components and systems described herein, such as control circuitry 350 (shown in FIG. 3 ), vehicle perception and planning system 220 (shown in FIG. 2 ), and vehicle control system 280 (shown in FIG. 2 ). Thus, the various method steps herein can be defined by the computer program instructions stored in main memory device 630 and/or persistent storage device 620 and controlled by processor 610 executing the computer program instructions. For example, the computer program instructions can be implemented as computer executable code programmed by one skilled in the art to perform an algorithm defined by the various method steps herein. Accordingly, by executing the computer program instructions, the processor 610 executes an algorithm defined by the methods of FIGS. 3-5 . Apparatus 600 also includes one or more network interfaces 680 for communicating with other devices via a network. Apparatus 600 may also include one or more input/output devices 690 that enable user interaction with apparatus 600 (e.g., display, keyboard, mouse, speakers, buttons, etc.).

Processor 610 may include both general and special purpose microprocessors and may be the sole processor or one of multiple processors of apparatus 600. Processor 610 may comprise one or more central processing units (CPUs), and one or more graphics processing units (GPUs), which, for example, may work separately from and/or multi-task with one or more CPUs to accelerate processing, e.g., for various image processing applications described herein. Processor 610, persistent storage device 620, and/or main memory device 630 may include, be supplemented by, or incorporated in, one or more application-specific integrated circuits (ASICs) and/or one or more field programmable gate arrays (FPGAs).

Persistent storage device 620 and main memory device 630 each comprise a tangible non-transitory computer readable storage medium. Persistent storage device 620, and main memory device 630, may each include high-speed random access memory, such as dynamic random access memory (DRAM), static random access memory (SRAM), double data rate synchronous dynamic random access memory (DDR RAM), or other random access solid state memory devices, and may include non-volatile memory, such as one or more magnetic disk storage devices such as internal hard disks and removable disks, magneto-optical disk storage devices, optical disk storage devices, flash memory devices, semiconductor memory devices, such as erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM), digital versatile disc read-only memory (DVD-ROM) disks, or other non-volatile solid state storage devices.

Input/output devices 690 may include peripherals, such as a printer, scanner, display screen, etc. For example, input/output devices 690 may include a display device such as a cathode ray tube (CRT), plasma or liquid crystal display (LCD) monitor for displaying information to a user, a keyboard, and a pointing device such as a mouse or a trackball by which the user can provide input to apparatus 600.

Any or all of the functions of the systems and apparatuses discussed herein may be performed by processor 610, and/or incorporated in, an apparatus or a system such as LiDAR system 300. Further, LiDAR system 300 and/or apparatus 600 may utilize one or more neural networks or other deep-learning techniques performed by processor 610 or other systems or apparatuses discussed herein.

One skilled in the art will recognize that an implementation of an actual computer or computer system may have other structures and may contain other components as well, and that FIG. 6 is a high-level representation of some of the components of such a computer for illustrative purposes.

FIG. 7A illustrates a front view of a vehicle 700 with an exemplary LiDAR system 710 comprising an isolation system in accordance with an embodiment. In the embodiment shown in FIG. 7A, LiDAR system 710 is disposed in a centered location 720 of top surface 730 of vehicle 700. However, in various other embodiments, LiDAR system 710 may be disposed in other locations of vehicle 700, including in one of an off-center location 740A or 740B of top surface 730, a side mirror location 750, or a door surface 750. Generally, the various embodiments herein may be implemented at any location on a vehicle in which LiDAR system 710 is disposed, and particularly at locations where undesirable acoustic noises and vibrations are most at-issue, e.g., locations proximate to a driver or passenger disposed within the vehicle.

FIG. 7B illustrates a left side view of a motor vehicle with an exemplary LiDAR system having an isolation system disposed in a top surface 730 of vehicle 700 according to an embodiment of the present disclosure. As described above, LiDAR system 710 may be disposed at different locations of vehicle 700. One ideal position of LiDAR system 710 may be top surface 730, e.g., at an edge location along the roof line of vehicle 700. For example, LiDAR system 710 may be disposed in top surface 730 for optimal scanning performance and Field of View (FOV).

FIG. 8A illustrates a perspective view of an exemplary isolation system for a LiDAR optical core assembly according to an embodiment of the present disclosure. In the embodiment shown in FIG. 8A, LiDAR optical core assembly 800 comprises a polygon-motor rotating element 810, an oscillating reflective element 820, and transmitting and collection optics 830. In some embodiments, the transmitting and collection optics 830 may comprise one or more transmitters configured to provide one or more transmission light beams. The transmitting and collection optics 830 may also include one or more collectors for collecting one or more return light beams. For example, the transmitter in the transmitting and collection optics 830 may transmit one or more laser light beams, which may be directed to oscillating reflective element 820. Oscillating reflective element 820 may move back and forth at a very high frequency. In some embodiments, oscillating reflective element 820 may be a galvanometer mirror, which is controllable to oscillate about an axis of the galvo. Oscillating reflective element 820 may direct the one or more transmission light beams to polygon-motor rotating element 810. In some embodiments, polygon-motor rotating element 810 may comprise a polygon mirror surface, which may be made of glass, to reflect light. Polygon-motor rotating element 810 may be driven by a motor to rotate around mirror axle 815, so as to steer and redirect light and illuminate objects located in an FOV.

In some embodiments, polygon-motor rotating element 810 may be adapted to rotate at speeds between about 3000-12000 revolutions per minute during the operation of optical core assembly 800. Polygon-motor rotating element 810, oscillating reflective element 820, and the transmitting and collection optics 830 may be adapted to maintain a substantially fixed alignment relative to each other during the operation of optical core assembly 800.

Further, an isolation system may be adapted to maintain the stability and reliability of optical core assembly 800 under large variations of the environmental conditions, such as imbalances, noises, shock displacements, vibrations, or other harsh conditions.

The isolation system of optical core assembly 800 may comprise a polygon-motor base element 840 and a plurality of isolators 850A-C. In particular, polygon-motor base element 840 may be coupled to polygon-motor rotating element 810. In some embodiments, polygon-motor base element 840 may be coupled to the polygon mirror axle of polygon-motor rotating element 810. Moreover, in some embodiments, polygon-motor base element 840 may further comprise a bracket portion 870. Bracket portion 870 may at least partially enclose polygon-motor rotating element 810. For example, in the embodiment shown in FIG. 8A, bracket portion 870 may at least partially enclose polygon-motor rotating element 810, such that bracket portion 870 may be configured to support and protect polygon-motor rotating element 810.

In some embodiments, the plurality of isolators may comprise at least three isolators, e.g., isolators 850A-C (referred to collectively herein as plurality of isolators 850). Bracket portion 870 may further comprise a plurality of flanges, which, in some embodiments, may be integrally formed parts of bracket portion 870. In some embodiments, the plurality of flanges may be disposed to receive the plurality of isolators 850. For example, in the embodiment shown in FIG. 8A, there are three integrally formed flanges 890 A-C (referred to collectively herein as plurality of flanges 890) disposed to receive the three isolators 850 A-C, respectively.

With reference still to FIG. 8A, the plurality of isolators 850 may be substantially fixed to polygon-motor base element 840 using corresponding ones of the plurality of flanges 890 of bracket portion 870. For example, isolator 850A may be substantially fixed to polygon-motor base element 840 using corresponding flange 890A, isolator 850B may be substantially fixed to polygon-motor base element 840 using corresponding flange 890B, and isolator 850C may be substantially fixed to polygon-motor base element 840 using corresponding flange 890C. In other embodiments that include additional isolators, the additional isolators may be substantially fixed to polygon-motor base element 840 using corresponding flanges in a similar manner.

FIG. 8B illustrates a top view of an exemplary isolation system for a LiDAR optical core assembly according to an embodiment of the present disclosure. In an embodiment, the plurality of isolators 850 may be disposed relative to each other and/or around a spatial location, e.g., a center of gravity. For example, as shown in FIG. 8B, the plurality of isolators 850 may be disposed relative to a spatial location 860 that is the center of gravity of optical core assembly 800. Notably, in order to be disposed relative to center of gravity 860, the plurality of isolators 850 may be asymmetrically disposed, and not necessarily equidistant from a particular location. Such a configuration may be due to various factors, including the configuration of the various other elements of optical core assembly 800 (e.g., the location of oscillating reflective element 820), the weights of the various other elements, the location of the LiDAR device comprising optical core assembly 800, or other factors.

In some embodiments, the plurality of isolators 850 may be adapted to support a maximum load at least equal to a total weight of the entire optical core assembly. Further, each of the plurality of isolators 850 may be adapted to support an equal amount of weight load. For example, in an exemplary embodiment, the total weight of the optical core assembly may be about 450 grams. Thus, each of the three isolators 850 may be adapted to support a maximum load amount of at least 150 grams.

In one exemplary embodiment shown in FIGS. 8A-8D, each of the isolators may comprise a synthetic rubber material, e.g., EPDM synthetic rubber, adapted to absorb energy and provide relatively high damping performance and low stiffness. In another exemplary embodiment, each of the plurality of isolators may comprise a grommet adapted provide sufficient load ratings and suitable mounting geometries, such as, e.g., the Vibracoustic® (VBC) DG0153 grommet. One skilled in the art will recognize that other isolator materials and/or grommets adapted to provide one or more of suitable energy absorption, relatively high damping properties, relatively low stiffness, sufficient load ratings, and suitable mounting geometries also may be suitable for the various embodiments herein.

FIG. 8C illustrates a right-side view of an exemplary isolation system for a LiDAR optical core assembly where the plurality of isolators 850 are disposed relative to each other around spatial location 860. In the embodiment shown in FIGS. 8B-8C, the plurality of isolators 850 are configured to center around spatial location 860. As noted above, spatial location 860 may be determined based on the center of gravity of optical core assembly 800. Alternatively, spatial location 860 may be determined based on the center of gravity polygon-motor rotating element 810.

Spatial location 860 may comprise a horizontal component and a vertical component. In an embodiment, the horizontal component may be used to locate the spatial location 860 in a horizontal plane. For example, in the embodiment shown in FIG. 8B, the spatial location 860 may correspond to the center of gravity of optical core assembly 800. As shown in FIG. 8B, the horizontal component of the spatial location 860 is displaced from the center of polygon-motor rotating element 810 to a location closer to oscillating reflective element 820. In this case, the center of gravity for the configuration of the three isolators 850 A-C may correspond to the center of gravity of the entire LiDAR optical core assembly. In another embodiment, the horizontal component of spatial location 860 may correspond to the axial center of polygon-motor rotating element 810. In this case, the horizontal component of the spatial location may also correspond to a location equidistant from each of the plurality of isolators 850 A-C. The center of gravity of the three isolators 850 A-C may correspond to the center of gravity of only polygon-motor rotating element 810.

The vertical component of the spatial location 860 may correspond to the height of the spatial location 860 in a vertical direction. In some embodiments, the vertical component of the spatial location 860 may correspond to the height of the center of gravity of the entire optical core assembly. In this case, as shown in FIG. 8B, the center of gravity of the three isolators 850 A-C may correspond to the center of gravity of the entire LiDAR optical core assembly. In some embodiments, the vertical component may correspond to the height of the center of gravity of polygon-motor rotating element 810. In this case, the center of gravity of the three isolators 850 A-C may correspond to the height of the center of gravity of only polygon-motor rotating element 810. In other embodiments, the vertical component may correspond to a vertical location between the height of the center of gravity of the entire optical core assembly and the height of the center of gravity of the polygon-motor rotating element 810.

The plurality of isolators 850 may be adapted to mitigate acoustic noise caused by at least polygon-motor rotating element 810 during the operation of optical core assembly 800. In some embodiments, an unmitigated audible sound level caused by the operation of optical core assembly 800 may be about 70-75 dB. In this case, the plurality of isolators 850 may be adapted to mitigate the acoustic noise caused by the operation of optical core assembly 800 to an audible sound level of less than 25 dB, or to a determined tolerable level depending on the driver's experience (or the experience of another passenger disposed within the vehicle). Furthermore, the plurality of isolators 850 may also be adapted to mitigate acoustic noise caused by at least one of an imbalance, a shock displacement, a vibration, a lateral wobble, or other directional displacement of polygon-motor rotating element 810 and/or oscillating reflective element (galvo) 820 during the operation of optical core assembly 800.

FIG. 8D illustrates an exploded view of an exemplary isolation system for a LiDAR optical core assembly according to an embodiment of the present disclosure. In some embodiments, in addition to bracket portion 870, the polygon-motor base element 840 may further comprise a plurality of fasteners 880 A-C (collectively referred to herein as plurality of fasteners 880). In some embodiments, each of the plurality of fasteners 880 may comprise a screw adapted to couple each of the plurality of isolators 850 to corresponding ones of the integrally formed flanges 890. For example, in the embodiment shown in FIG. 8D, polygon-motor base element 840 may further comprise three fasteners 880 A-C. The three fasteners 880 A-C may be adapted to couple each of the three isolators 850 A-C to each corresponding integrally formed flanges 890 A-C, respectively. It should be understood that the plurality of isolators 850 may comprise more than three isolators (e.g., 4 isolators, 5 isolators, 6 isolators, 7 isolators, or 8 or more isolators) as long as the weight load of each isolator 850 is within an optimal performance range of each isolator 850, and sufficient space is available to arrange the isolators within the LiDAR system. Correspondingly, polygon-motor base element 840 may comprise more than three fasteners 880 (e.g., 4 fasteners, 5 fasteners, 6 fasteners, 7 fasteners, or 8 or more fasteners), and bracket portion 870 may comprise more than three flanges 890 (e.g., 4 flanges, 5 flanges, 6 flanges, 7 flanges, or 8 or more flanges) disposed to receive the isolators 850, respectively.

FIG. 9A illustrates a perspective view of another exemplary isolation system for a LiDAR optical core assembly 900 according to another embodiment of the present disclosure. As shown in FIG. 9A, the LiDAR optical core assembly 900 comprises a polygon-motor rotating element 910, an oscillating reflective element 920, and transmitting and collection optics 930. In some embodiments, the transmitting and collection optics 930 may comprise one or more transmitters configured to provide one or more transmission light beams. The transmitting and collection optics 930 may also include one or more collectors for collecting one or more return light beams. For example, the transmitter in the transmitting and collection optics 930 may transmit one or more laser light beams, which may be directed to the oscillating reflective element 920. The oscillating reflective element 920 may move back and forth at a very high frequency. In some embodiments, the oscillating reflective element 920 may be a galvanometer mirror, which is controllable to oscillate about an axis of the galvo. The oscillating reflective element 920 may direct the one or more transmission light beams to the polygon-motor rotating element 910. In some embodiments, the polygon-motor rotating element 910 may comprise a polygon mirror surface, which may be made of glass, to reflect light. The polygon-motor rotating element 910 may be driven by a motor to rotate around a mirror axle 915, so as to steer and redirect light and illuminate objects located in an FOV.

In some embodiments, the polygon-motor rotating element 910 may be adapted to rotate at speeds between about 3000-12000 revolutions per minute during the operation of the optical core assembly. The polygon-motor rotating element 910, the oscillating reflective element 920, and the transmitting and collection optics 930 may be adapted to maintain a substantially fixed alignment relative to each other during the operation of optical core assembly 900.

Further, an isolation system may be adapted to maintain the stability and reliability of the optical core assembly under large variations of the environmental conditions, such as imbalances, noises, shock displacements, vibrations, or other harsh conditions. The isolation system of LiDAR optical core assembly 900 may comprise a polygon-motor base element 940 and a plurality of isolators 950A-C. In particular, the polygon-motor base element 940 may be coupled to the polygon-motor rotating element 910. In some embodiments, the polygon-motor base element 940 may be coupled to the polygon mirror axle of the polygon-motor rotating element 910. Moreover, in some embodiments, polygon-motor base element 940 may further comprise a bracket portion 970. Bracket portion 970 may at least partially enclose the polygon-motor rotating element 910. For example, in the embodiment shown in FIG. 9A, bracket portion 970 may at least partially enclose polygon-motor rotating element 910, such that bracket portion 970 may be configured to support and protect polygon-motor rotating element 910.

In some embodiments, the plurality of isolators may comprise at least three isolators, e.g., isolators 950A-C (referred to collectively herein as plurality of isolators 950). Bracket portion 970 may further comprise a plurality of flanges, which, in some embodiments, may be integrally formed parts of bracket portion 970. In some embodiments, the plurality of flanges may be disposed to receive the plurality of isolators 950. For example, in the embodiment shown in FIG. 9A, there are three integrally formed flanges 990 A-C (referred to collectively herein as plurality of flanges 990) disposed to receive the three isolators 950 A-C, respectively.

With reference still to FIG. 9A, the plurality of isolators 950 may be substantially fixed to polygon-motor base element 940 using corresponding ones of the plurality of flanges 990 of bracket portion 970. For example, isolator 950A may be substantially fixed to polygon-motor base element 940 using corresponding flange 990A, isolator 950B may be substantially fixed to polygon-motor base element 940 using corresponding flange 990B, and isolator 950C may be substantially fixed to polygon-motor base element 940 using corresponding flange 990C. In other embodiments including additional isolators, the additional isolators may be substantially fixed to polygon-motor base element 940 using corresponding flanges in a similar manner.

FIG. 9B illustrates a top view of an exemplary isolation system for a LiDAR optical core assembly according to an embodiment of the present disclosure. In an embodiment, the plurality of isolators 950 may be disposed relative to each other and/or around a spatial location, e.g., a center of gravity. For example, as shown in FIG. 9B, the plurality of isolators 950 may be disposed relative to a spatial location 960 that is the center of gravity of optical core assembly 900. Notably, in order to be disposed relative to center of gravity 960, the plurality of isolators 950 may be asymmetrically disposed, and not necessarily equidistant with respect to a particular location. Such a configuration may be due to various factors, including the configuration of the various other elements of optical core assembly 900 (e.g., the location of oscillating reflective element 920), the weights of the various other elements, the location of the LiDAR device comprising optical core assembly 900, or other factors.

In some embodiments, the plurality of isolators 950 may be adapted to support a maximum load at least equal to a total weight of the entire optical core assembly. Further, each of the plurality of isolators 950 may be adapted to support an equal amount of weight load. For example, in an exemplary embodiment, the total weight of the optical core assembly may be about 450 grams. Thus, each of the three isolators 950 may be adapted to support a maximum load amount of at least 150 grams.

In one exemplary embodiment shown in FIGS. 9A-9C, each of the isolators may comprise a synthetic rubber material, e.g., 3M E-A-R™ SL-20300 synthetic rubber, adapted to absorb energy and provide relatively high damping and low stiffness performance. In another exemplary embodiment, each of the plurality of isolators may comprise a grommet adapted provide sufficient load ratings and suitable mounting geometries, such as, e.g., the 3M®—Aearo Technologies LLC G-411 grommet. One skilled in the art will recognize that other isolator materials and/or grommets adapted to provide one or more of suitable energy absorption, relatively high damping properties, relatively low stiffness, sufficient load ratings, and suitable mounting geometries also may be suitable for the various embodiments herein.

The isolation system for a LiDAR optical core assembly 900 shown in FIGS. 9A-9C may further comprise one or more soft stop elements 955 A-C (collectively as 955) disposed between each of the corresponding fasteners and isolators. Each of the isolators 950 may correspond to one or more soft stop elements 955. In an embodiment, the one or more soft stop elements 955 may be adapted to further limit displacement of optical core assembly 900, e.g., to within 1 mm of a nominal position. The one or more soft stop elements may also comprise a synthetic rubber material, e.g., 3M E-A-R™ SL-20300 synthetic rubber, to absorb energy and reduce the displacement of the elements or parts of the optical core assembly.

FIG. 9C illustrates a right-side view of an exemplary isolation system for a LiDAR optical core assembly where the plurality of isolators 950 are disposed relative to each other around spatial location 960. In the embodiment shown in FIGS. 9B-9C, the plurality of isolators 950 are configured to center around spatial location 960. As noted above, spatial location 960 may be determined based on the center of gravity of optical core assembly 900. Alternatively, spatial location 960 may be determined based on the center of gravity polygon-motor rotating element 910.

In an embodiment, spatial location 960 may comprise a horizontal component and a vertical component.

The horizontal component may be used to locate the spatial location 960 in a horizontal plane. For example, in the embodiment shown in FIG. 9B, the spatial location 960 may correspond to the center of gravity of optical core assembly 900. As shown in FIG. 9B, the horizontal component of the spatial location 960 is displaced from the center of polygon-motor rotating element 910 to a location closer to oscillating reflective element 920. In this case, the center of gravity for the configuration of the three isolators 950 A-C may correspond to the center of gravity of the entire LiDAR optical core assembly. In another embodiment, the horizontal component of spatial location 960 may correspond to the axial center of polygon-motor rotating element 910. In this case, the horizontal component of the spatial location may also correspond to a location equidistant from each of the plurality of isolators 950 A-C. The center of gravity of the three isolators 950 A-C may correspond to the center of gravity of only polygon-motor rotating element 910.

The vertical component of the spatial location 960 may correspond to the height of the spatial location 960 in the vertical direction. In some embodiments, the vertical component of the spatial location 960 may correspond to the height of the center of gravity of the entire optical core assembly. In this case, as shown in FIG. 9B, the center of gravity of the three isolators 950 A-C may correspond to the center of gravity of the entire LiDAR optical core assembly. In some embodiments, the vertical component may correspond to the height of the center of gravity of polygon-motor rotating element 910. In this case, the center of gravity of the three isolators 950 A-C may correspond to the height of the center of gravity of only polygon-motor rotating element 910. In other embodiments, the vertical component may correspond to a vertical location between the height of the center of gravity of the entire optical core assembly and the height of the center of gravity of the polygon-motor rotating element 910.

The plurality of isolators 950 may be adapted to mitigate acoustic noise caused by at least polygon-motor rotating element 910 during the operation of optical core assembly 900. In some embodiments, an unmitigated audible sound level caused by the operation of the optical core assembly 900 may be about 70-75 dB. In this case, the plurality of isolators 950 may be adapted to mitigate the acoustic noise caused by the operation of optical core assembly 900 to an audible sound level of less than 25 dB, or to a determined tolerable level depending on the driver's experience (or the experience of another passenger disposed within the vehicle). Furthermore, the plurality of isolators 950 may also be adapted to mitigate acoustic noise caused by at least one of an imbalance, a shock displacement, a vibration, a lateral wobble, or other directional displacement of polygon-motor rotating element 910 and/or oscillating reflective element (galvo) 920 during the operation of optical core assembly 900.

In some embodiments, in addition to bracket portion 970, the polygon-motor base element 940 may further comprise a plurality of fasteners 980 A-C (collectively referred to herein as plurality of fasteners 980). In some embodiments, each of the plurality of fasteners 980 may comprise a screw adapted to couple each of the plurality of isolators 950 to corresponding ones of the integrally formed flanges 990. For example, in the embodiment shown in FIGS. 9A-9C, polygon-motor base element 940 may further comprise three fasteners 980 A-C. The three fasteners 980 A-C may be adapted to couple each of the three isolators 950 A-C to each corresponding integrally formed flanges 990 A-C, respectively. It should be understood that the plurality of isolators 950 may comprise more than three isolators (e.g., 4 isolators, 5 isolators, 6 isolators, 7 isolators, or 8 or more isolators) as long as the weight load of each isolator 950 is within an optimal performance range of each isolator 950, and sufficient space is available to arrange the isolators within the LiDAR system. Correspondingly, polygon-motor base element 940 may comprise more than three fasteners 980 (e.g., 4 fasteners, 5 fasteners, 6 fasteners, 7 fasteners, or 8 or more fasteners), and bracket portion 970 may comprise more than three flanges 990 (e.g., 4 flanges, 5 flanges, 6 flanges, 7 flanges, or 8 or more flanges) disposed to receive the isolators 950, respectively.

FIG. 10 illustrates an exemplary isolation system for a LiDAR optical core assembly with a base according to an embodiment of the present disclosure. In the embodiment shown in FIG. 10 , LiDAR optical core assembly may at least comprise a polygon-motor rotating element 1010, an oscillating reflective element 1020, and transmitting and collection optics 1030. The LiDAR optical core assembly may be attached, secured, coupled to or supported by the base 1140. In some embodiments, the base 1140 may also be a bottom enclosure, baseplate, frame, housing or support structure. The plurality of fasteners 980 may be further adapted to couple the polygon-motor base element to an inner surface of the base 1040 for the optical core assembly. The base 1140 may further limit the displacement of the LiDAR optical core assembly caused by the noises, shocks, vibrations, lateral wobbles or other harsh conditions. As discussed herein, the LiDAR optical core assembly comprises elements pertaining to a LiDAR system. However, the scope of the various embodiment disclose herein may cover other types of delicate systems or instruments, such as other types of light detection systems or instruments that has high requirements on the accuracy of the system.

FIG. 11A illustrates a perspective views of an exemplary isolation system for a LiDAR optical core assembly with a base 1140 and an enclosure 1110 according to an embodiment of the present disclosure. In the embodiment of FIG. 11A, the enclosure 1110 may be a housing, walls, covers, or other structures to at least partially enclose polygon-motor rotating element 1010 and the enclosure 1110 may be used to house and/or protect the various components of the polygon-motor rotating element 1010. In some embodiments, the plurality of fasteners 950 may be further adapted to couple the polygon-motor base element to the inner surface of the enclosure 1110 for the optical core assembly.

FIG. 11B illustrates a zoomed-in perspective view of an exemplary isolation system for a LiDAR optical core assembly with a base 1140 and an enclosure 1110 according to the embodiment shown in FIG. 11A. The enclosure 1110 may have an opening at one side facing the oscillating reflective element 1020. The Opening 1104 may allow light beams to be directed in or out of the enclosure 1110 or the transmitting and collection optics 1030, and allow light beams to be directed to or from the oscillating reflective element 1020 or the polygon-motor rotating element 1010. The enclosure 1110 may reduce the air vibration caused by the high-speed rotation of polygon-motor rotating element 1010, thereby reducing the noise or vibrations surrounding the polygon-motor rotating element 1010. The enclosure 1110 may also facilitate a smoother rotation of polygon-motor rotating element 1010. In turn, the smoother rotation improves the overall light scanning performance and energy efficiency of the LiDAR optical core assembly.

The foregoing specification is to be understood as being in every respect illustrative and exemplary, but not restrictive, and the scope of the invention disclosed herein is not to be determined from the specification, but rather from the claims as interpreted according to the full breadth permitted by the patent laws. It is to be understood that the embodiments shown and described herein are only illustrative of the principles of the present invention and that various modifications may be implemented by those skilled in the art without departing from the scope and spirit of the invention. Those skilled in the art could implement various other feature combinations without departing from the scope and spirit of the invention. 

What is claimed is:
 1. An isolation system for a light detection and ranging (LiDAR) optical core assembly having at least a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics, the isolation system comprising: a polygon-motor base element coupled to the polygon-motor rotating element; and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element, wherein the plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.
 2. The system of claim 1, wherein the polygon-motor base element comprises: a bracket portion that at least partially encloses the polygon-motor rotating element, the bracket portion having integrally formed flanges disposed to receive the plurality of isolators; and a plurality of fasteners adapted to couple each of the plurality of isolators to corresponding ones of the integrally formed flanges.
 3. The system of claim 2, wherein the plurality of fasteners is further adapted to couple the polygon-motor base element to an inner surface of an enclosure for the optical core assembly.
 4. The system of claim 1, wherein the polygon-motor base element is coupled to a polygon mirror axle of the polygon-motor rotating element.
 5. The system of claim 1, wherein the plurality of isolators is adapted to support a load at least equal to a total weight of the optical core assembly.
 6. The system of claim 1, wherein each of the plurality of isolators is adapted to support an equal amount of load.
 7. The system of claim 6, wherein each of the plurality of isolators to adapted to support a load of at least 150 grams.
 8. The system of claim 1, wherein each of the plurality of isolators comprises a synthetic rubber material.
 9. The system of claim 1, wherein each of the plurality of isolators comprises a grommet.
 10. The system of claim 1, wherein the plurality of isolators comprises at least three isolators.
 11. The system of claim 1, wherein the spatial location corresponds to the center of gravity of the optical core assembly.
 12. The system of claim 1, wherein the spatial location corresponds to the center of gravity of the polygon-motor rotating element.
 13. The system of claim 1, wherein the spatial location is disposed between the center of gravity of the optical core assembly and the center of gravity of the polygon-motor rotating element.
 14. The system of claim 1, wherein a horizontal component of the spatial location corresponds to a location equidistant from each of the plurality of isolators, and a vertical component of the spatial location corresponds to a height of the center of gravity.
 15. The system of claim 1, wherein an unmitigated audible sound level caused by the operation of the optical core assembly is 70 75 dB.
 16. The system of claim 15, wherein the plurality of isolators is adapted to mitigate the acoustic noise caused by the operation of the optical core assembly to an audible sound level of less than 25 dB.
 17. The system of claim 1, wherein the acoustic noise is caused by at least one of an imbalance, a shock displacement, a vibration, a lateral wobble, or other directional displacement of the polygon-motor rotating element during operation of the optical core assembly.
 18. The system of claim 1, wherein the polygon-motor rotating element is adapted to rotate at speeds between 3000-12000 revolutions per minute during the operation of the optical core assembly.
 19. The system of claim 1, wherein the polygon-motor rotating element, the oscillating reflective element, and the transmitting and collection optics are adapted to maintain a substantially fixed alignment relative to each other during operation of the optical core assembly.
 20. The system of claim 1, further comprising one or more stop elements adapted to limit displacement of the optical core assembly.
 21. The system of claim 20, wherein the one or more stop elements are adapted to limit displacement of the optical core assembly within 1 mm of a nominal position.
 22. The system of claim 20, wherein the plurality of isolators comprises the one or more stop elements.
 23. A LiDAR scanning system comprising an isolation system for a light detection and ranging (LiDAR) optical core assembly having at least a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics, the isolation system comprising: a polygon-motor base element coupled to the polygon-motor rotating element; and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element, wherein the plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.
 24. The LiDAR scanning system of claim 23, wherein the LiDAR scanning system is coupled to a vehicle.
 25. The LiDAR scanning system of claim 24, wherein the LiDAR scanning system is coupled to a roof element of the vehicle.
 26. The LiDAR scanning system of claim 24, wherein the LiDAR scanning system is coupled to a location on the vehicle corresponding to a determined location of maximum structural rigidity.
 27. A vehicle comprising a LiDAR scanning system, wherein the LiDAR scanning system comprises an isolation system for a light detection and ranging (LiDAR) optical core assembly having at least a polygon-motor rotating element, an oscillating reflective element, and transmitting and collection optics, the isolation system comprising: a polygon-motor base element coupled to the polygon-motor rotating element; and a plurality of isolators substantially fixed to the polygon-motor base element and disposed relative to each other around a spatial location determined based on a center of gravity of at least one of the optical core assembly and the polygon-motor rotating element, wherein the plurality of isolators is adapted to mitigate acoustic noise caused by at least the polygon-motor rotating element during operation of the optical core assembly.
 28. The vehicle of claim 27, wherein the isolation system further comprises one or more stop elements adapted to limit displacement of the optical core assembly during operation of the vehicle.
 29. The vehicle of claim 28, wherein the one or more stop elements are adapted to limit displacement of the optical core assembly within 1 mm of a nominal position during operation of the vehicle. 